ML20210P144

Forwards Safety Evaluation Accepting Util 861224 Response to TMI Action Item II.K.3.31,compliance w/10CFR50.46 by Referencing WCAP-11145, Westinghouse Small Break LOCA ECCS Evaluation Model Generic Study W/Notrump Code

ML20210P144
Person / Time
Site:	Byron
Issue date:	02/05/1987
From:	Olshan L Office of Nuclear Reactor Regulation
To:	Farrar D COMMONWEALTH EDISON CO.
References
TASK-2.K.3.31, TASK-TM NUDOCS 8702130310
Download: ML20210P144 (4)

Text

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February 5,1987 '

-Docket Nos. STN 50-454 DIST ]LTMON P.MFF'NRC PDR STN 50-455 Local PDR PD#3 Rdg.

Mr. D. L. Farrar T. Novak OGC Director of Nuclear Licensing

'E. Jordan B. Grimes Comonwealth Edison Company J. Partlow N. Thompson Post Office Box 767 L. Olshan C. Vogan Chicago, Illinois 60600 ACRS (10)

SUBJECT:

TMI ACTION ITEM II.K.3.31, COMPLIANCE WITH 10 CFR 50.46 -

BYRON STATION, UNITS 1 AND 2 By letter dated December 24, 1986, you responded to TMI Action Item II.K.3.31, Compliance with 10 CFR 50.46, by referencing WCAP-11145, " Westinghouse Small Break LOCA ECCS Evaluation Model Generic Study with the NOTRUMP code."

Enclosed is our Safety Evaluation which concludes that the Byron FSAR analyses of small break LOCA have been demonstrated to be conservative in comparison with the NOTRUMP Evaluation Model, and that Byron meets the requirements of II.K.3.31 and 10 CFR 50.46.

Sincerely, Leonard N. 01shan, Project Manager Project Directorate #3 Division of PWR Licensing-A

Enclosure:

As stated cc: See next page PD#3h PD#3 CVggan hL01shan 2/ /87 2/5/87 9

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8702130310 870205 DR ADOCK 05000454 PDR

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Mr. Dennis L. Farrar Ryron ' Station Comonwealth Edison Company Units 1 and 2 CC*

Mr. William Kortier Ms. Diane Chavez Atomic Power Distribution 528 Gregory Street Westinahouse Electric Corporation-

_Rockford, Illinois 61108 Post Office Box 355 Pittsburgh, Pennsylvania 15230 Regional Administrator, Region III U. S. Nuclear Regulatory Comission Michael Miller-799 Roosevelt Road Isham, Lincoln & Beale Glen Ellyn, Illinois 60137-One First National Plaza 42nd Floor Joseph Gallo, Esq.

Chicago, Illinois 60603 Isham, Lincoln & Beale Suite 1100 Mrs. Phillip B. Johnson 1150 Connecticut Avenue, N.W.

1907 Stratford Lane Washington, D. C.

20036 Rockford, Illinois 61107 Douglass Cassel, Esq.

Dr. Bruce von Zellen 109 N. Dearborn Street Department of Biological Sciences Suite 1300 Northern Illinois University Chicago, Illinois 6060?

DeKalb, Illinois 61107 Ms. Pat Morrison Mr. Edward R. Crass 5568 Thunderidge Drive Nuclear Safeguards & Licensing Rockford, Illinois 61107 h

Sargent & Lundy Engineers 55 East Monroe Street Ms. Lorraine Creek Chicago, Illinois 60603 Rt. 1, Box 182 Manteno, Illinois 60950 l

Mr. Julian Hinds U. S. Nuclear Regulatory Comission l

Byron / Resident Inspectors Offices 4448 German Church Road i

Byron, Illinois 61010 Mr. Michael C. Parker, Chief Division of Engineering Illinois Department of Nuclear Safety 1035 Outer Park Drive Springfield, Illinois 62704 I

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O ENCLOSURE 1

- 15.9.14 II.K.3.31 Plant-Specific Calculations to Show Compliance with 10 CFR 50.46 Safety Evaluation by the Peactor Systems Branch for Byron, Units 1 8 2 Section II.K.3.30 of NUREG-0737 outlines the Commission requirements for the industry to demonstrate that its small break LOCA methods continue to comply with the requirements of Appendix K to 10 CFR 50. The technical issues to be addressed were listed in NUREG-0611 including comparision with semiscale experimental test results.

In response to Section II.K.3.30, the Westinghouse Owners Group elected to reference the NOTPtlFP code as the new licensing small break LOCA model. The NOTRUPP code and methodology are described in WCAP 10079 and WCAP-10054. The staff reviewed and approved NOTRUMP as the new licensing tool for calculating small break LOCA response for Westinghouse plant designs.

The staff further concluded that the Festinghouse Owners Group had met the requirements of Section II.K.3.30.

Referencing the new computer code did not imply deficiencies in the WFLASH code (which was previously utilized for small break LOCA analysis) such that the code did not comply with Appendix K to 10 CFR 50. The decision to use NOTRUMP was based on desires of the industry to perfom licensing evaluations with a computer program specifically designed to calculate small break LOCAs with greater phenomenological accuracy than capable by WFLASH.

Section II.K.3.31 of NUREG-0737 required that each license holder or applicant submit a new small break analysis using the model approved under II.K.3.30.

NRC Generic Letter 83-35 provided clarification for the II.K.3.31 requirements by allowing license holders and applicants to comply on a generic basis by demonstrating that the WFLASH analyses are conservative when compared to analyses perfomed using NOTRUPP.

in response to this guidance the Westinghouse owners submitted WCAP-111a5 I

which contains generic comparisons to WFLASH analyses for various plant t

types. These include comparisons for 4-loop plants of the Byron, Units 1 & P l

design.

If plant specific analyses were perfomed for Byron, Units 1 & 2 using NOTRUMP, lower peak clad temperatures should be expected in comparison with the l

generic NOTRUMP analysis (about 537'F lower than the 1,790'F PCT currently I

calculated with VFLASH SRLOCA EM).

Although the calculated peak temperatures are significantly lower for the NOTRUMP analyses than for the WFLASH analyses the 4 inch break remains the limiting break size.

.._____.m.

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Staff review of WCAP-11145 has been completed and accepted as a licensing basis for SBLOCA analysis. The applicant has referenced WCAP-11185 (which consists of the results from calculations using approved methodology) in lieu of sutwitting a plant specific analysis and meets the criteria as stated in NPC Generic letter 83-35. The staff, therefore, concludes that the Byron, Units 1 E 2 FSAR analyses of small break LOCA have been demonstrated to be conservative in comparison with the NOTRUMP Evaluation Mcdel. This meets the requirements of !!.X 3.31 and 10 CFR 50.A6 for Byron Units 1 & P.

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